North Korea is "willing to denuclearise" and the US is prepared to end hostile relations, President Moon Jae-in said Thursday as he struck an upbeat tone ahead of his third meeting with Kim Jong Un next week.
The summit will be the third between the leaders of North and South Korea this year and comes as talks between Washington and Pyongyang over dismantling the North's nuclear arsenal have stalled.
Moon conceded there was a "blockage" and both sides needed to compromise to make progress on the controversial subject.
"North Korea is willing to denuclearise and therefore willing to discard existing nuclear weapons... and the US is willing to end hostile relations with the North and provide security guarantees," Moon said.
"But there is a blockage as both sides are demanding each other to act first and I think they will be able to find a point of compromise."
Moon, who helped broker the June summit between Kim and US President Donald Trump and has called for a follow-up meeting between the two sides, added South Korea would help mediate contacts between Washington and Pyongyang to "speed up the denuclearisation process".
Trump and Kim Jong Un pledged to denuclearise the Korean peninsula at their historic Singapore meeting.
However, no details were agreed, and Washington and Pyongyang have sparred since over what that means and how it will be achieved. Last month, Trump abruptly cancelled a planned visit by Secretary of State Mike Pompeo to Pyongyang.
The new US envoy for the North, Stephen Biegun, said in August Kim had promised "final, fully verified denuclearisation" at the Singapore summit.
But Pyongyang has slammed Washington for its "gangster-like" demands for complete, verifiable and irreversible disarmament.
South Korea's Foreign Minister Kang Kyung-wha said Thursday that making progress on denuclearisation talks with North Korea is a "daily concern".
"Getting traction on the denuclearisation and peace process that is very much now in motion -- it's a daily concern to get movement on this," she told a regional economic forum in the Vietnamese capital Hanoi.
Speaking on the sidelines of the forum, Kang called for "openness" from the North about their weapons programme and added a second Trump-Kim summit should deliver "concrete" results.
"A second summit has to be something that really significantly moves the agenda forward," she added.
The White House said earlier this week Trump had received a "very positive" letter from Kim seeking a follow-up meeting, since adding it is in the process of coordinating a possible second meeting between the two leaders.
South Korean national security advisor Chung Eui-yong said Thursday Moon and Kim will discuss "more in-depth and detailed ways to achieve denuclearisation".
The two Koreas will be holding a closed working-level meeting on Friday to discuss the logistics of next week's summit, an official at the South's presidential office said.